This invention relates to improved wall lifting systems used during the construction of framed structures. More particularly, this invention relates to providing a system for safe, efficient lifting of partially fabricated walls during light-frame construction.
In typical light-frame construction, walls are partially fabricated in a horizontal position, typically at ground level, and are subsequently raised to a vertical position during assembly of the wall. Framed walls tend to be large and unwieldy requiring a large work crew to manually lift the framing into place. Manually raised framed walls can become too heavy and unstable for the lifting personnel and can collapse back onto workers located under the structure. This problem is often compounded when raising large multi-story wall sections (balloon framing), due to the increased weight and height of the sections. In the United States, the Occupational Safety and Health Administration (OSHA) has documented numerous injuries related to accidents occurring during the lifting of framed walls, including injuries that resulted in death.
As the popularity of light-framed construction increased, framing contractors developed a variety of rudimentary techniques for the manual lifting of such walls; however, these improvised techniques are often of marginal safety benefit and frequently rely heavily on a construction foreman guessing the weight of a wall and estimating the number of workers necessary to perform the lift. Many lifting failures can be attributed to insufficient numbers of lifting personnel resulting in inadequate support during the lift.
Thus, a need exists for a safe, efficient, and secure system to assist in the lifting of framed wall structures, thereby minimizing the costly hazards associated with such work.